Fuel injection devices



May 22, 1962 P. E. BESSIERE 3,035,562

FUEL INJECTION DEVICES Filed July 25, 1960 2 Sheets-Sheet 1 INVEN TOR 7/5475 ti -151v: Piss/:45

a $61? My;

ATTORNEXS May 22, 1962 P. E. BESSIERE 3,035,562

FUEL INJECTION DEVICES Filed July 25, 1960 2 Sheets-Sheet 2 NVE N TOR United States i atent @fhee 3,935,562 Patented May 22, 1962 3,035,562 FUEL INJECTION DEVICES Pierre Etienne Bessiere, 55 Blvd. Charcot, Neuilly-sur-Seine, France Filed July 25, 1960, Ser. No. 45,157 Claims priority, application France Aug. 31, 1959 7 Claims. (Cl. 123-139) This invention relates to fuel injection devices, in which the same piston-cylinder assembly of a reciprocating pump feeds a plurality of injectors through the medium of a distributor; and it relates more especially, but not exclusively, to devices of this kind serving for the supply of fuel to a plurality of cylinders of an internal combustion engine (an explosion engine, a progressive combustion engine, such as a diesel engine, and so on).

The object of the invention is to make these devices such that they satisfy in a more satisfactory manner than hitherto the various requirements occurring in practice and that, in particular, the pressures prevailing in the conduits connecting, on the one hand, the aforesaid piston-cylinder assembly to the distributor and, on the other hand, the latter to the various injectors, should have the desired values.

The invention consists principally in providing separate discharge means, on the one hand, for the common conduit connecting the piston-cylinder assembly to the distributor and, on the other hand, for the individual conduits which connect the distributor to the various injectors, and in controlling said discharge means, preferably by the distributor, in such manner that those serving to discharge the common conduit are brought into communication with the latter after each injection by one of the injectors and before the beginning of the next injection by another injector and those serving to discharge the individual conduits are brought into communication with each of the latter at least once between two consecutive injections by said individual conduit.

Preferred embodiments of the present invention will be hereinafter described with reference to the accompanying drawings, given merely by way of example, and in which:

FIG. 1 is a diagrammatic view of the essential elements of a fuel injection device in a multi-cylinder engine, this device being constructed according to a first embodiment of the invention.

FIG. 2 is a modification of the device shown in FIG. 1.

FIG. 3 shows still another modification. 1

FIG. 4 shows another embodiment of the distributor forming part of the injection device illustrated in any of the preceding figures.

The device which will now be described is for the in jection of fuel in the four cylinders of an internal combustion engine from a single pump piston-cylinder assembly.

The reciprocating injection pump containing the said piston-cylinder assembly is made for instance as illustrated in FIGURE 1, according to which the piston 1 of the pump performing outgoing and return movement in its cylinder 2 effects the beginning of the delivery of the pump by the closure of the feed conduit 3 of the latter, while it produces the end of the injection period by the re-opening of said feed conduit by means of a control surface 4 forming an incline and bounding a groove 5 formed in the side wall of the piston 1 and connected by a conduit 6 to the interior of the cylinder 2. In order to vary the part of the incline 4 which re-opens the feed conduit 3 and thus vary the output of the pump on each delivery stroke of the latter, means (not shown) are provided, which enable the piston 1 to be turned about its axis independently to its outgoing and return movements which are communicated to it, for example, by a cam or any other appropriate kinematic device, which is driven by the motor on which the injection installation in question is mounted, so that the number of outgoing and return movements of the piston 1 is always proportional to the number of revolutions of the engine.

The cylinder 2 also contains a delivery valve 7 (arranged for example in the form of a re-suction valve, but it may also be simply a ball valve) and a delivery conduit 8. The reciprocating pump may naturally be arranged in various other ways.

Irrespective of the construction of the reciprocating pump, its delivery conduit 8, hereinafter referred to as the common delivery conduit, is connected to a distributor 9, in the bore 9a of which an element 10 rotates,

which is driven at an appropriate speed proportional to 4 that of the engine on which the injection device in question is fitted.

During each of the successive delivery strokes of the piston 1 of the pump, the rotary element 10 connects the common delivery conduit 3 successively to a plurality of injectors (not shown) through individual feed conduits 11 11 etc., which are connected with the bore 9a of the distributor 9. For this purpose, the side surface of the rotary element 10 of the distributor is provided with a longitudinal groove 12 in communication with an annular groove 13 formed in the said element 19 opposite the point where the delivery conduit 8 opens into the bore 9a and this longitudinal groove 12 connects annular groove 13 successively with the respective feed conduits 11 11 etc..

For good operation of a device such as described hereinbefore, it is important that the pressure prevailing immediately before every injection period in the conduits connecting the piston-cylinder assembly to the various injectors be at least approximately the same for all successive injections so that all the injectors operate in the same way and, especially, deliver the same amount of fuel to their respective engine cylinders. On the other hand between successive injection periods, it is not necessary to have the same pressure in all the portions of every circuit intended to connect the reciprocating pump cylinder with one of the injectors.

Thus it is frequently advantageous to maintain, between two consecutive injection periods, in the common delivery conduit 8, a pressure higher than that prevailing in the individual conduits .11 11 Another case is the one in which a re-suction valve is interposed in each of the individual conduits. In that case, it is advantageous for the pressure upstream of this valve to be sufficiently low to promote a quick closing of this re-suction valve.

In order to make an injection device of the kind in question capable of satisfying these various conditions, according to the main feature of the invention separate dis charge means are provided, on the one hand, for the common conduit 8 and, on the other hand, for the individual conduits 11 11 and so on, and these discharge means are preferably controlled by the distributor itself in such manner that after each period during which injection takes place through one of the injectors, on the one hand, the conduit 8 and, on the other hand, at least that one of the individual conduits 1.1 11 etc., through which the previous injection took place are brought into communication by different paths with discharge spaces.

For this purpose, the surface of the rotary element 19 of the distributor situated on the left of the groove 13 is formed with as many grooves 14 as there are injection periods during a complete rotation of the said element 10,

and a discharge conduit 15 starts from the zone of the bore 9a which is swept by these grooves 14. The angular distribution of the grooves 14 in the surface of the element 10 and the position of the opening of the conduit 15 in the wall of the bore 9a are so chosen in relation to the angular arrangement of the grooves 12 and of the openings of the individual conduits 11 11 etc. in the wall of the bore 9a, that the groove 13 and with it the delivery conduit 8 are brought into communication with the discharge conduit 15 between two consecutive injection periods.

In order to maintain in the conduit 8 a pressure greater than that prevailing in the space to which the conduit 15 leads, the said conduit is provided either with a throttle 16 or with a counter-pressure valve 17 (see FIGURE 2), the calibration of which determines the residual pressure in the conduit 8.

With regard to the discharge of the individual conduits 11 11 and so on, the rotary element 19 of the distributor is advantageously formed with a second groove 18 and the surface of this element situated between the two grooves 13 and 18 is advantageously formed with another longitudinal groove 19 which leads into the groove 18 and which extends as far as the transverse Zone in which the openings of the individual conduits 11 11 etc. are situated. The groove 19 is disposed in a radial plane which in relation to the direction of rotation of the rotary element 10 is situated behind the radial plane in which the groove 12 is formed. The ofisetting between these two grooves is so selected that after the end of the injection period through a determined injector and before the beginning of the next injection period through the same injector the corresponding individual conduit is brought into communication by the groove 19 and the groove 18 with a discharge conduit 20 separate from the discharge conduit 15.

It will frequently be advantageous also to provide in this conduit .20 either a throttle 21 or a counter-pressure valve 22, in order to maintain in each of the individual conduits 11 11 etc., between two injections taking place through the same conduit, a residual pressure which will thusbe the same for all these individual conduits but which will advantageously be different from the residual pressure in the conduit 8. The maintenance of a lower pressure in the individual conduits has the advantage of preveting parasitic injections as might be caused by the accidental opening of an injector as a consequence of a shock (such an opening being possible if the pressure is too high in the individual conduits). On the other hand, a high residual pressure in the conduit 8 gives rise to an automatic variation of the lead in the right direction because then the lead is all the more reduced the lower the speed of drive of the pump.

In other cases it is advantageous to omit from the discharge conduit 20 any means such as a throttle 21 or a calibrated valve 22 which would give rise to a considerable residual pressure in the part of the conduit 20 situated upstream of these means. A case of this kind is the one in which there is provided in the individual conduits 11 11 and so on, re-suction valves 23 (see FIGURE 3). When such valves are provided in the individual conduits, it is in fact advantageous to promote as much as possible the rapid closure of these valves. It is obvious that this closure is effected all the more rapidly as the pressure upstream of the said valves is lower. Moreover, these valves maintain the required residual pressure between them and the corresponding injectors.

In the distributor of the kind illustrated in FIGURE 1, a single groove 19 is formed in the surface of the rotary element 10 of the said distributor. In consequence, the various individual conduits 11 11 etc., are successively brought into communication with the discharge conduit 20 in the same sequence as that in which injec' tion took place through these same individual conduits.

The distributor illustrated in FIGURE 4 differs from that shown in FIGURE 1 in that it contains as many grooves 19a as there are individual conduits 11 11 etc. The distribution of these grooves 19a over the rotary element 10 is such that after each injection period through one of the individual conduits all these conduits are brought into communication simultaneously with the discharge conduit 2t) and with one another. In this case, the angular offsetting of the grooves 19a on the element 10 must be chosen in such manner that this communication between the individual conduits and the discharge conduit takes place between two consecutive injection periods. The purpose of this arrangement is to make sure that, even if the engine fed by the pump is running at very high speed (Le. if distributor 910 is rotating at very high speed) each of the individual feed conduits 11 11 etc. is placed in communication, between two injections therethrough with discharge conduit 20 for a total time sufiicient to ensure the return of the pressure in said individual conduit to the desired value.

Irrespective of the embodiment adopted, the result is always a fuel injection device, the operation and advantages of which are clearly apparent from the foregoing, so that it is unnecessary to give any further explanation in connection therewith.

It will be understood and is further apparent from the foregoing that the invention is in no way limited to the embodiments thereof which have. been more especially considered.

In a general manner, while I have, in the above description, disclosed what I deem to be practical and efficient embodiment of my invention, it should be Well understood that I do not wish to be limited thereto as there might be changes made in the arrangement, disposition and form of the parts without departing from the principle of the present invention as comprehended within the scope of the accompanying claims.

What I claim is:

1. For use with an engine comprising a plurality of injectors, a fuel injection device including a plurality of individual conduits leading to said injectors respectively, a reciprocating pump, a common delivery conduit leading out from said pump, whereby a flow of fuel is fed through said conduit only during every delivery stroke of said pump, a distributor having an inlet in communication with said common conduit and a plurality of outlets in communication with said individual conduits respectively, said distributor being capable of connecting said inlet with each of said outlets successively during the delivery strokes of said pump, a first discharge conduit, means for placing said first discharge conduit in communication with said common delivery conduit once during every time interval between two consecutive injector operations, at least one other discharge conduit and means for placing said last mentioned discharge conduit in com.- munication with each of said individualconduits at least once during every time interval between two consecutive operations of the injector connected with said last mentioned individual conduit.

2. A device according to claim 1 further including means mounted in said first discharge conduit for maintaining a given residual pressure in said common conduit.

3. A device according to claim 1 further including means mounted in said discharge conduits for maintaining given residual pressure in said common conduit and said individual conduits.

4. A device according to claim 1 further including means mounted in said discharge conduits for maintaining given residual pressures in said common conduit and said individual conduits, said last mentioned means being adapted to maintain a higher residual pressure in said common conduit than in said individual conduits.

5. For use with an engine comprising a plurality of injectors, a fuel injection device including a plurality of individual conduits leading to said injectors respectively,

a reciprocating pump, a common delivery conduit leading out from said pump, whereby a flow of fuel is fed through said conduit only during every delivery stroke of said pump, a distributing valve including a cylindrical casing and a rotating cylindrical body therein, said casing being provided with a port through which said common conduit opens thereinto, said cylindrical body being provided with an annular groove opposite said first mentioned port, said casing being provided with a plurality of ports through which said individual conduits open into said casing, said plurality of ports being disposed all on one side of said annular groove, said cylindrical body being provided with a passage connecting said groove with each of the ports of said plurality of ports, successively, as said body is rotating, during the delivery strokes of said pump, a first discharge conduit opening into said casing at a point thereof located on the other side of said annular groove, said cylindrical body being provided with a plurality of passages connecting said annular groove with said last mentioned point of the periphery of said body once during every time interval between two consecutive communications established by said first mentioned passage between said groove and said individual conduits, a second discharge conduit opening into said casing at a point thereof located on the other side of said plurality of ports from said annular groove, said cylindrical body being provided with a second annular groove opposite said last mentioned point, said cylindrical body being provided with at least one passage connecting said second annular groove with each of the ports of said plurality of ports, successively, as said body is rotating.

6. A device according to claim 5, in which said cylindrical body is provided with a plurality of passages distributed angularly therein in the same manner as the ports of said individual conduits, the number of said last mentioned passages being equal to the number of individual conduits so as to connect said second groove with all of said individual conduits once during every time interval between the communications of said first mentioned groove with two consecutive individual conduits. 7. For use with an engine comprising a plurality of injectors, a fuel injection device which comprises a plurality of individual conduits leading to said injectors respectively, a distributor having a fixed part from which said individual conduits start and a movable part, said movable part being provided with a fuel delivery recess adapted to communicate with each of said individual conduits respectively, reciprocating means for supplying a liquid pressure in said delivery recess during every time period for which it is in communication with one of said individual conduits, a first discharge conduit, means for placing said delivery recess in communication with said discharge conduit once during every interval between two successive such time periods, at least one other discharge conduit and means for placing said last mentioned discharge conduit in communication with each of said individual conduits at least once during every time interval between two consecutive operations of the injector connected with said last mentioned individual conduit.

References Cited in the file of this patent UNITED STATES PATENTS 1,236,045 Bessiere June 7, 1960 FOREIGN PATENTS 596,690 Germany May 9, 1934 666,491 Germany Oct. 21, 1953 

